Merge pull request Lead-Studios#190 from Godsmiracle001/feature/pagination

Implemented pagination module and service in common folder(171)
closes Lead-Studios#190

Author: BigBen-7

backend/src/app.module.ts

@@ -28,8 +28,15 @@ import { RedisService } from './guest/provider/redis.service';
 import { GuestUserController } from './guest/guest.controller';
 import { GuestUserService } from './guest/guest.service';
 import { MailModule } from './mail/mail.module';
+
+import { PaginationModule } from './common/pagination/pagination-controller.controller'; // Your change
+
+
+
+
 import { DictionaryModule } from './dictionary/dictionary.module';
 
+
 @Module({
   imports: [
     ConfigModule.forRoot({
@@ -62,6 +69,8 @@ import { DictionaryModule } from './dictionary/dictionary.module';
     ResultModule,
     SubAdminModule,
     GuestModule,
+    PaginationModule, 
+    MailModule, 
     GamemodeModule,
     GuestUserModule,
     GuestFeaturesModule,
@@ -71,4 +80,4 @@ import { DictionaryModule } from './dictionary/dictionary.module';
   controllers: [AppController, GuestUserController],
   providers: [AppService, GuestUserGuard, RedisService, GuestUserService], // Provide RedisService & GuestGuard globally
 })
-export class AppModule {}
+export class AppModule {}

backend/src/common/pagination/dto/pagination-query-dto.dto.ts

@@ -0,0 +1,24 @@
+import { IsOptional, IsPositive, IsNumber, Min, IsString } from "class-validator";
+import { Type } from "class-transformer";
+
+export class PaginationQueryDto {
+  @IsOptional()
+  @Type(() => Number)
+  @IsNumber()
+  @Min(1)
+  page?: number = 1;
+
+  @IsOptional()
+  @Type(() => Number)
+  @IsNumber()
+  @Min(1)
+  limit?: number = 10;
+
+  @IsOptional()
+  @IsString()
+  sort?: string;
+
+  @IsOptional()
+  @IsString()
+  filter?: string;
+}

backend/src/common/pagination/interfaces/pagination-interface.ts

@@ -0,0 +1,17 @@
+// an interface is a way to define the shape of an object, describing the structure and types of its properties
+export class paginated<T> {
+    data: T[];
+    meta: {
+      itemsPerPage: number;
+      totalItemsPerPage: number;
+      currentPage: number;
+      totalPages: number;
+    };
+    links: {
+      firstPage: string;
+      lastPage: string;
+      previousPage: string;
+      currentPage: string;
+      nextPage: string;
+    };
+  }

backend/src/common/pagination/pagination-controller.controller.ts

@@ -0,0 +1,8 @@
+import { Module } from "@nestjs/common";
+import { PaginationService } from "./provider/pagination-service.service";
+
+@Module({
+  providers: [PaginationService],
+  exports: [PaginationService],
+})
+export class PaginationModule {}

backend/src/common/pagination/provider/pagination-service.service.ts

@@ -0,0 +1,79 @@
+import { Injectable, Inject } from "@nestjs/common";
+import {
+	ObjectLiteral,
+	Repository,
+	FindOptionsWhere,
+	FindOptionsOrder,
+} from "typeorm";
+import { Request } from "express";
+import { REQUEST } from "@nestjs/core";
+import { paginated } from "../interfaces/pagination-interface";
+import { PaginationQueryDto } from "src/common/pagination/dto/pagination-query-dto.dto";
+
+@Injectable()
+export class PaginationService {
+	constructor(
+		@Inject(REQUEST)
+		private readonly request: Request
+	) {}
+
+	public async paginationQuery<T extends ObjectLiteral>(
+		paginatedQueryDto: PaginationQueryDto,
+		repository: Repository<T>
+	): Promise<paginated<T>> {
+		const { limit = 10, page = 1, sort, filter } = paginatedQueryDto;
+
+		// Handle sorting with correct type
+		const order: FindOptionsOrder<T> = {};
+		if (sort) {
+			const isDescending = sort.startsWith("-");
+			const columnName = isDescending ? sort.substring(1) : sort;
+			(order as any)[columnName] = isDescending ? "DESC" : "ASC"; // Type assertion to match FindOptionsOrder<T>
+		}
+
+		// Prepare filtering options
+		const where: FindOptionsWhere<T>[] | undefined = filter
+			? [
+					{ name: filter } as unknown as FindOptionsWhere<T>,
+					{ description: filter } as unknown as FindOptionsWhere<T>,
+				]
+			: undefined;
+
+		// Fetch paginated results
+		const [result, totalItems] = await repository.findAndCount({
+			where,
+			order,
+			skip: limit * (page - 1),
+			take: limit,
+		});
+
+		const totalPages = Math.ceil(totalItems / limit);
+		const currentPage = page;
+		const nextPage = page < totalPages ? page + 1 : totalPages;
+		const previousPage = page > 1 ? page - 1 : 1;
+
+		// Construct base URL
+		const baseUrl = `${this.request.protocol}://${this.request.headers.host}`;
+		const newUrl = new URL(this.request.url, baseUrl);
+
+		// Construct paginated response
+		const finalResponse: paginated<T> = {
+			data: result,
+			meta: {
+				itemsPerPage: limit,
+				totalItemsPerPage: totalItems,
+				currentPage: page,
+				totalPages: totalPages,
+			},
+			links: {
+				firstPage: `${newUrl.origin}${newUrl.pathname}?limit=${limit}&page=1`,
+				lastPage: `${newUrl.origin}${newUrl.pathname}?limit=${limit}&page=${totalPages}`,
+				currentPage: `${newUrl.origin}${newUrl.pathname}?limit=${limit}&page=${currentPage}`,
+				previousPage: `${newUrl.origin}${newUrl.pathname}?limit=${limit}&page=${previousPage}`,
+				nextPage: `${newUrl.origin}${newUrl.pathname}?limit=${limit}&page=${nextPage}`,
+			},
+		};
+
+		return finalResponse;
+	}
+}